JPH07242846A - Ink, method for forming picture image by the same ink and device using the same ink - Google Patents

Abstract

PURPOSE:To obtain an ink having an excellent clear color tone, a high concen tration, water resistance, improved storage stability and delivery stability free from clogging of a nozzle. CONSTITUTION:This ink contains 0.1-20.0wt.% (especially preferably 0.5-10.0wt.%) of a salt-formed material of dye prepared by salt forming a cationic dye with a compound of formula I or formula II [R is a 5-22C alkyl; R<1> is H or methyl; R<2> is a 5-12C alkyl; X is COOM (M is H, an alkali metal or ammonium), SO3M or OSO3M; (n) is 1 or 2; (p) is 0 or 2] as a coloring material. C5H11CON(CH3)CH2CH2COONa may be cited as the compound of formula I and C8H17OCOCH(SO3Na)CH2COONa as the compound of formula II. A mixture of water and a polar organic solvent is used as a liquid medium of the ink.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink, a method for forming an image with the ink, and an apparatus using the ink, and in particular, ejection from a nozzle is stable. An ink capable of forming a recorded image having high print density, clear color development, good water resistance, and less bleeding (feathering) on so-called plain paper such as bond paper and report paper. And an apparatus using such an ink.

[0002]

2. Description of the Related Art Conventionally, an aqueous ink prepared by dissolving a water-soluble dye in an aqueous medium has been used as an ink for ink jet recording. For this ink for inkjet recording, (a) an image with sufficient density can be obtained, (b)
Good fixability on the recording material, (c) little bleeding of the recorded image, (d) the recorded image does not flow out even when it comes into contact with water or alcohol, or the recorded image flows out. Even if it is, it has sufficient water resistance and is readable, (e) a recorded image with excellent light resistance can be obtained, (f) no clogging occurs at the pen tip or nozzle tip, (g) It has ejection stability that does not cause blurring in the recorded image during continuous recording or when recording is started after being left for a long time. (h) Good storage stability That is, (i) it is stable even when it comes into contact with the members constituting the recording means at the time of use, (j) for the user,
Various performances such as no safety issues are required.

Further, in addition to the above items, (k) heat resistance is excellent for inks used in an ink jet recording system utilizing heat energy, and adverse effects are exerted on heat energy generating means. It is required not to reach. In addition to the above items, in addition to the above items, for inks used in inkjet recording systems that perform color recording, (l) the color development is clear and it is possible to reproduce a color tone that is faithful to the original color. ) When inks of different colors are adjacent to each other on the recording material, performances such as no mixing (bleeding) are required.

These performances of the ink are of course dependent on the composition components of the ink, but are largely governed by the characteristics of the coloring material contained in the ink.
There is no existing ink that uses a dye as a coloring material and that satisfies all of the above various performances.

In particular, as a conventional water-based ink for ink jet recording, an existing acid dye or a direct dye is mainly used as a coloring material, but an ink satisfying all the above-mentioned performances has not been obtained. . Further, an ink containing a cationic dye as a coloring material is suitable as an ink for color recording in that a high-density image exhibiting a clear color tone can be obtained, but a drawback is that the water resistance is extremely poor. There is.

Furthermore, JP-A-51-47823, JP-A-51-30019, and JP-A-51-31526.
JP-A-54-98807, JP-A-54-
Japanese Patent No. 131427 describes an ink containing a dye salt-forming material obtained by salting a basic dye with a specific compound as a coloring material. In addition, JP-A-56-131678 and JP-A-5-
JP-A-7-25376 describes an ink in which a salt-forming product of a basic dye and an anion activator or a salt-making product of a basic dye and an organic acid is combined with an ethylene oxide addition type surfactant. ing. However, all of these inks are intended to improve drying resistance and water resistance in applications such as writing instruments and stamps, and various performances required for the ink for inkjet recording described above. However, these inks cannot satisfy various performances required of inks for ink jet recording.

Further, in Japanese Patent Publication No. 58-6752, an ink containing an ethylene oxide adduct of a tertiary alcohol is contained as an ink having excellent properties in ejection stability, storage stability, fixability and water resistance. However, this ink is not yet sufficient in water resistance, bleeding of a recorded image is likely to occur, and the quality of the obtained image is not satisfactory.

[0008]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to obtain a high-density image having a clear color tone on various types of plain paper, and to obtain perfect water resistance by blurring the recorded image. Ink having good storage stability, no nozzle clogging, and excellent ejection stability when used as an ink for inkjet recording. An object of the present invention is to provide an image forming method using the ink and a device using the ink.

[0009]

The above object can be achieved by the present invention described below. That is, the present invention provides an ink comprising a liquid composition containing a coloring material and a liquid medium for dissolving or dispersing the coloring material, wherein the coloring material is a cationic dye represented by the following general formula (A) or (B). An ink characterized by containing a salt-forming dye salt formed by the salt-forming compound represented by
An image forming method using the ink and an apparatus using the ink. [In the general formulas (A) and (B), R has 5 to 2 carbon atoms.
2 is an alkyl group, R ¹ is a hydrogen atom or a methyl group,
² is an alkyl group having 5 to 12 carbon atoms, X is -COOM,-
A group selected from SO ₃ M and —OSO ₃ M, M represents a hydrogen atom, an alkali metal or ammonium, n represents 1 or 2, and p represents 0 or 2. ]

[0010]

According to the present invention, for example, so-called plain paper such as high-quality paper, copy paper, bond paper, report paper and the like, so-called plain paper, has a clear color tone, high density, and complete water resistance, so that bleed An ink capable of forming a recorded image with less occurrence, good storage stability, and free from nozzle clogging, and particularly excellent in ejection stability during inkjet recording. It is possible to provide an image forming method and a device using the ink.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments. Specific preferred examples of the cationic dye used in the present invention include C.I. I. Basic Yellow 1, C.I. I. Basic Yellow 11,
C. I. Basic Yellow 12, C.I. I. Basic Orange 14, C.I. I. Basic Orange 21, C.I.
I. Basic Red 1, C.I. I. Basic Red 2, C.I. I. Basic Red 3, C.I. I. Basic Red 4, C.I. I. Basic Red 8, C.I. I. Basic Red 9, C.I. I. Basic Red 12, C.I.
I. Basic Red 13, C.I. I. Basic Violet 1, C.I. I. Basic Violet 3, C.I.
I. Basic Violet 4, C.I. I. Basic Violet 5, C.I. I. Basic Violet 7,
C. I. Basic Violet 10, C.I. I. Basic Violet 11, C.I. I. Basic Blue 1,
C. I. Basic Blue 3, C.I. I. Basic Blue 5, C.I. I. Basic Blue 8, C.I. I. Basic Blue 9, C.I. I. Basic Blue 15, C.I. I.
Basic Blue 18, C.I. I. Basic blue 2
0, C.I. I. Basic Blue 26, C.I. I. Basic Green 1, C.I. I. Basic Green 4, C.I.
I. Basic Black 2, C.I. I. Acid red 5
1, C.I. I. Acid Red 94, C.I. I. Acid Red 95, C.I. I. Acid Red 98 and the like can be mentioned, but the present invention is not limited thereto.

The following general formula (A) used when a salt-forming dye is obtained by reacting with a cationic dye [In the formula, R represents an alkyl group having 5 to 22 carbon atoms, R ¹ represents a hydrogen atom or a methyl group, X represents a group selected from —COOM, —SO ₃ M, and —OSO ₃ M, and M represents hydrogen. An atom, an alkali metal or ammonium, and n represents 1 or 2, respectively. ] Specific examples of the salt-forming compound represented by
For example, (1) C ₅ H ₁₁ CON (CH ₃ ) CH ₂ CH ₂ CO
ONa (2) C ₁₁ H ₂₃ CON (CH ₃ ) CH ₂ COONH
₄ (3) C ₁₅ H ₃₁ CON (CH ₃ ) CH ₂ CH ₂ SO
₃ Na (4) C ₂₁ H ₄₃ CONHCH ₂ CH ₂ OSO ₃ Li and the like can be mentioned, but the invention is not limited thereto.

Similarly, the following general formula (B) [In the formula, R ² represents an alkyl group having 5 to 12 carbon atoms, M represents a hydrogen atom, an alkali metal or ammonium, and p represents 0 or 2. Specific examples of the salt-forming compound represented by: (5) C ₈ H ₁₇ OCOCH (SO ₃ Na) CH ₂ CO
ONa (6) C ₁₆ H ₃₃ OCOCH (SO ₃ Na) CH ₂ C
OONa (7) C ₂₂ H ₄₅ O (OC ₂ H ₄ ) ₂ OCOCH (S
O ₃ Na) CH ₂ COONa and the like can be mentioned, but the present invention is not limited thereto.

Specific examples of the ethylene oxide adduct of a tertiary alcohol used as an ink component include the following general formula (C). [In the formula, L ¹ is-(OCH ₂ CH ₂ ) _x OH, L ² is-(OCH ₂ CH ₂ ) _y OH, and x and y are 1 to 3 respectively.
It represents an integer of 0, and x and y may be the same. ]
In the above, each compound of x + y = 8 to 30 can be mentioned.

The ink containing the ethylene oxide adduct of the tertiary alcohol has the effect of stabilizing the solubility of the dye-enriched salt by the addition of the ethylene oxide adduct, so that the storage stability described in the required performance (h) is satisfied. Will be good. At the same time, the pen tip and the tip of the nozzle described in the required performance (f) are not clogged. Further, after the continuous recording described in the required performance (g) or at the time of restarting the recording after being left for a long time, the ejection stability is improved without causing a blur in the recorded image. In general, when a dye-enriched salt is contained in an inkjet ink, when the solubility of the dye-enhanced salt is low, the ejection characteristics may deteriorate.
Particularly in such a case, the addition of the ethylene oxide adduct of the tertiary alcohol is effective. Therefore, by adding ethylene oxide of a tertiary alcohol to the ink of the present invention, a special effect that it can be preferably used as an inkjet ink is obtained.

In the ink of the present invention, an aqueous solution of a cationic dye and a solution of a salt-forming compound represented by the general formula (A) or (B) are mixed in an equimolar ratio to form an insoluble dye salt-forming compound. It is obtained by separating and drying this, and dissolving it in a predetermined liquid medium. Further, in the ink of the present invention, the compound represented by the general formula (C) and other additives such as a pH adjusting agent, an antifungal agent and a viscosity adjusting agent are added if necessary.

In the ink of the present invention, the amount of the dye salt-forming agent produced by increasing the salt of the cationic dye in the ink with the salt-forming compound represented by formula (A) or (B) is Although not particularly limited, it is generally 0.1 to 20.0% by weight, preferably 0.2 to 1 of the total ink.
5.0% by weight, more preferably 0.5-10.0% by weight
It is a degree.

The amount of the ethylene oxide adduct of the tertiary alcohol represented by the general formula (C) to be used depends on the solubility of the above dye salt in the liquid medium, the wetting of the ink on the orifice surface of the head, and the stable ejection of the ink. Since it affects the image quality, image quality, water resistance, etc., it is determined in consideration of the influence on these properties, but is usually 0.1 to 15.0% by weight of the ink, preferably 0.5 to 10%. 0% by weight, more preferably 1.
It is about 0 to 5.0% by weight.

A suitable liquid medium in the ink of the present invention is
Water or a mixture of water and a water-soluble organic solvent, and deionized water is particularly preferable as water. Examples of the water-soluble organic solvent used by mixing with water include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-
Butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-pentanol and the like having 1 to 5 carbon atoms
Alkyl alcohols; amides such as dimethylformamide and dimethylacetamide; ketones or keto alcohols such as acetone and diacetone alcohol; ethers such as dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol, propylene Alkylene groups such as glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol and diethylene glycol have 2 to 6 alkylene groups.
Alkylene glycols containing 1 carbon atom; glycerin; polyhydric alcohols such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, and triethylene glycol monoethyl ether Lower alkyl ethers; lower dialkyl ethers of polyhydric alcohols such as triethylene glycol dimethyl ether, triethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether; sulfolane, N-methyl-2-pyrrolidone, 1,3 -Dimethyl-2-imidazolidinone and the like.

The suitable liquid medium in the ink of the present invention is as described above, but the ink of the present invention is a salt-forming compound represented by the general formula (A) or (B), which is a cationic dye as a coloring material. From the viewpoint of preventing clogging of the ink, diethylene glycol or thiodiglycol is preferable since the dye-salt forming agent is used. From the viewpoint of obtaining excellent image density and ejection stability, a nitrogen-containing cyclic compound or an ether compound of polyalkylene oxide is preferable. Furthermore, from the viewpoint of frequency response, it is preferable to use a lower alcohol or a surfactant. Therefore, the preferable composition of the liquid medium in the ink of the present invention is water and various components as described above.

In the ink of the present invention, the content of the water-soluble organic solvent in the ink is generally from 2 to 80% by weight, preferably from 3 to 70% by weight, more preferably from the total weight of the ink. It is 4 to 60% by weight. In the ink of the present invention, the content of water used as a suitable liquid medium is
10 to 97.5% by weight of the total weight of the ink, preferably 3
It is 5 to 97.5% by weight, and more preferably 45 to 97.5% by weight. If the amount of water in the ink is less than 10% by weight, a large amount of low-volatile organic solvent remains in the formed recorded image, causing problems such as migration of color materials and image bleeding.

The ink of the present invention contains a pH adjusting agent, a viscosity adjusting agent, a surface tension adjusting agent and the like, if necessary, in addition to the above components. Examples of the pH adjuster include various organic amines such as diethanolamine and triethanolamine, and inorganic alkali agents such as alkali metal hydroxides such as sodium hydroxide, lithium hydroxide and potassium hydroxide. Further, the ink of the present invention has a viscosity at 25 ° C. of 1 to 20 cps, preferably 1 to 15 cps, and a surface tension of 20 dyn / cm or more, preferably 3
It is 0 dyn / cm or more, and the pH is about 6 to 10.

An ink jet recording method is effective as a recording method using the ink of the present invention, and as a recording material, general plain paper (for example, high quality paper, medium quality paper or bond paper), Any of coated paper, plastic film for OHP, etc. can be used.

The ink of the present invention is particularly suitable for use in an ink jet recording method of the type in which ink is ejected due to the bubbling phenomenon of ink due to thermal energy.
The ejection of the ink is extremely stable, and satellite dots are not generated. However, in this case, it may be necessary to adjust thermal physical properties such as specific gravity, thermal expansion coefficient, and thermal conductivity. The ink of the present invention is
It is particularly suitable for an ink jet recording method in which droplets are ejected for recording by the action of thermal energy, but it goes without saying that it can also be used as a general writing tool.

As a recording method and apparatus suitable for recording using the ink of the present invention, an ink jet which gives thermal energy corresponding to a recording signal to the ink in the chamber of the recording head and generates a droplet by the energy. The recording method and apparatus are mentioned. Hereinafter, such an inkjet recording device will be described.

An example of the structure of the head, which is the main part, is shown in FIGS. FIG. 1 is a schematic cross-sectional view of the head 13 along the ink flow path, and FIG. 2 is a schematic cross-sectional view showing a cross-sectional view taken along the line AB of FIG. The head 13 has a groove 1 through which ink passes.
It is obtained by adhering a glass, ceramics or plastic plate or the like having No. 4 and a heating head 15 (a thin film head is shown in the figure, but not limited to this) used for thermal recording. The heating head 15 includes a protective film 16 made of silicon oxide and an aluminum electrode 17.
-1 and 17-2, a heating resistor layer 18 formed of nichrome, a heat storage layer 19, and a substrate 2 having good heat dissipation such as alumina.
It consists of zero.

The ink 21 is a discharge orifice (fine hole) 2
It is filled up to 2, and a meniscus 23 is formed by a pressure (not shown). Now, when an electric signal is applied to the electrodes 17-1 and 17-2, the area indicated by n of the heating head 15 rapidly generates heat, and bubbles are generated in the ink 21 in contact therewith, and the meniscus 23 is generated by the pressure. Is ejected, the ink 21 is ejected, and the ink droplet 2 is ejected from the ejection orifice 22.
4 and fly toward the recording material 25.

Further, FIG. 3 shows an example of a multi-head in which a large number of the heads shown in FIG. 1 are arranged. The multi-head is made by bonding a glass plate 27 having multi-grooves 26 and a heating head 28 similar to that described in FIG.

FIG. 4 shows an example of an ink jet recording apparatus incorporating this head. In FIG. 4, reference numeral 65 denotes a recording head having ejection energy generating means, which ejects ink onto a recording material facing the ejection port surface where the ejection ports are arranged to perform recording, and 66 is equipped with the recording head 65. A carriage for moving the lever. The carriage 66 has a guide shaft 6
7, and a part of the carriage 66 is connected to a belt 69 driven by a motor 68 (not shown). As a result, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move in the recording area and the area adjacent thereto. 5
Reference numeral 1 is a paper feed section for inserting a recording material, and 52 is a paper feed roller driven by a motor (not shown). With these configurations, the recording material is fed to a position facing the ejection opening surface of the recording head 65, and as recording progresses, the recording material is ejected to a paper ejection unit provided with a paper ejection roller 53.

Reference numeral 61 denotes a blade as a wiping member, one end of which is held by a blade holding member to become a fixed end, which is in the form of a cantilever. Blade 61
Is arranged at a position adjacent to the recording area of the recording head 65, and in the case of this example, is held in a protruding form in the movement path of the recording head 65. Reference numeral 62 denotes a discharge port cap of the recording head 65, which is arranged at a home position adjacent to the blade 61 and is configured to move in a direction perpendicular to the moving direction of the recording head 65 and contact the discharge surface for capping. Equipped. Further, 63 is an ink absorber provided adjacent to the blade 61, and like the blade 61, is held in a form protruding in the movement path of the recording head 65. The blade 61, the cap 62, and the absorber 63 constitute an ejection recovery unit 64, and the blade 61 and the absorber 63 remove water, dust, and dust on the ink ejection port surface.

In the above structure, when the recording head 65 returns to the home position after recording is completed, the head recovery unit 64
The cap 62 is retracted from the moving path of the recording head 65, but the blade 61 is projected in the moving path.
As a result, the ejection port surface of the recording head 65 is wiped. When the cap 62 comes into contact with the ejection surface of the recording head 65 to perform capping, the cap 62 moves so as to project into the movement path of the recording head.

When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same position as the above-mentioned position at the time of wiping. As a result, even in this movement, the ejection port surface of the recording head 65 is wiped. Recording head 65 described above
Is moved to the home position adjacent to the recording area at a predetermined interval while the recording head 65 is moving in the recording area for recording, not only when the recording is completed or when the ejection is recovered. The wiping is performed along with the movement.

FIG. 5 is a diagram showing an example of an ink cartridge 45 containing ink to be supplied to the head through a supply tube. Reference numeral 40 denotes a storage portion for storing the supply ink, for example, an ink bag, and a rubber stopper 42 is provided at the tip thereof. By inserting a needle (not shown) into this stopper 42, the ink in the ink bag 40 can be supplied to the head. Reference numeral 44 is an absorber that receives waste ink. In the present invention, it is preferable that the liquid contact surface of the ink containing portion with the ink is formed of polyolefin, particularly polyethylene.

The ink jet recording apparatus in which the ink of the present invention is used is not limited to the above-described head and ink cartridge as separate bodies, but those in which they are integrated as shown in FIG. Is also preferably used. In FIG. 6, 70 is an ink jet cartridge,
An ink absorber impregnated with ink is housed therein, and the ink in the ink absorber is ejected as ink droplets from a head portion 71 having a plurality of orifices. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the cartridge with the atmosphere. The inkjet cartridge 70 is used in place of the recording head 65 shown in FIG. 4, and is detachable from the carriage 66.

[0035]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. Example (a) Preparation of Dye Salt-Forming Compound The following compounds (1) to (6) were used as the salt-forming compound represented by the following general formula (A) or (B). [In the general formulas (A) and (B), R has 5 to 2 carbon atoms.
2 is an alkyl group, R ¹ is a hydrogen atom or a methyl group,
² is an alkyl group having 5 to 12 carbon atoms, X is -COOM,-
A group selected from SO ₃ M and —OSO ₃ M, M represents a hydrogen atom, an alkali metal or ammonium, n represents 1 or 2, and p represents 0 or 2. ]

(1) C ₅ H ₁₁ CON (CH ₃ ) CH
₂ CH ₂ COONa (2) C ₁₁ H ₂₃ CON (CH ₃ ) CH ₂ COON
H ₄ (3) C ₁₅ H ₃₁ CON (CH ₃ ) CH ₂ CH ₂ S
O ₃ Na (4) C ₂₁ H ₄₃ CONHCH ₂ CH ₂ OSO ₃ L
_{i (5) C 8 H 17} OCOCH (SO 3 Na) CH 2 C
OONa (6) C ₁₆ H ₃₃ OCOCH (SO ₃ Na) CH ₂
COONa Each of the cationic dyes and the compounds (1) to (6) for salt formation are reacted with each other by the combinations shown in Table 1 below,
Dye salt forming products (I) to (VI) were obtained.

[0037]

[Table 1]

(B) Ethylene oxide adducts used The following (8) to (10) were used as ethylene oxide adducts of tertiary alcohols represented by the following general formula (C) (hereinafter abbreviated as ethylene oxide adducts). [In the formula, L ¹ is-(OCH ₂ CH ₂ ) _x OH, L ² is-(OCH ₂ CH ₂ ) _y OH, and x and y are 1 to 3 respectively.
It represents an integer of 0, and x and y may be the same. ]

(8) x + y = 8 to 12 (9) x + y = 12 to 20 (10) x + y = 20 to 30 (c) Preparation of ink The dye salt forming compounds (I) to (VI) and the ethylene oxide adduct ( 8) to (10), the components shown in Tables 2 and 3 below were mixed and dissolved, and then the pore size was 0.2.
Filtration was performed with a μm filter to obtain six types of ink of the present invention.

[0040]

[Table 2]

[0041]

[Table 3]

Comparative Example (a) Preparation of Dye Salt Forming Agents Each of the cationic dyes and the organic acid or anion activator were reacted with the combinations shown in Table 4 below to obtain dye salt forming compounds (i) to (vi). ) Got.

[0043]

[Table 4] Note) (*) in the above table indicates the product name.

(B) Preparation of ink Using the dye salt-forming compounds (i) to (vi) and the ethylene oxide adducts (8) to (10), the components shown in Tables 5 to 7 below were mixed. , After dissolution, pore size 0.2μm
Then, 10 kinds of inks of comparative examples were obtained.

[0045]

[Table 5] Note) (*) in the above table represents the trade name of the ethylene oxide addition type activator.

[0046]

[Table 6] Note) (*) in the above table represents the trade name of the ethylene oxide addition type activator.

[0047]

[Table 7]

On-demand type multi-head (orifice diameter) in which each ink of Evaluation Examples 1 to 6 and Comparative Examples 1 to 10 is subjected to recording by applying thermal energy to the ink in the recording head to generate droplets. 40 × 40 μm, drive voltage 32 V, frequency 3.5 kHz) mounted on a recording device for printing,
Each evaluation shown below was performed. The evaluation results are shown in Table 8 below.

(A) Printing Density A solid patch is printed on two types of plain paper for copiers (Canon NP paper and Xerox 4024 paper) by simultaneously driving all nozzles, the optical density of the printing is measured at several points, and the average value thereof is measured. Was evaluated according to the following criteria. A: 1.25 or more B: 1.20 or more and less than 1.25 C: 1.00 or more and less than 1.20 D: less than 1.00 The optical density is Macbeth reflection densitometer TR-524 type. It was measured using.

(B) Occurrence rate of feathering Feathering is continuously printed on two types of plain paper for copiers (Canon NP paper and Xerox 4024 paper) so that dots do not come into contact with each other. The proportion (%) of dots having bleeding was counted by an optical microscope, and the average value was used for evaluation according to the following criteria. A: less than 5% B: 5% or more and less than 10% C: 10% or more and less than 20% D: 20% or more

(C) Fixability Two types of plain paper for copiers (Canon NP paper and Xerox 4024 paper) are used for alphanumeric characters (60 characters x 40 lines, A4 size).
(Size) and the average time required (seconds) until the print does not fade even when rubbed with lens cleaning paper from the hand.
Was measured and evaluated according to the following criteria. A: Less than 10 seconds B: 10 seconds or more and less than 15 seconds C: 15 seconds or more and less than 30 seconds D: 30 seconds or more

(D) Water resistance (d-1) A solid patch prepared in the same manner as in (a) above was gently immersed in tap water at 20 ° C. for 1 hour and then dried to obtain the optical density of the print before and after immersion. Was measured at several points, and the average value of the reduction rate was evaluated according to the following criteria. A: less than 5% B: 5% or more and less than 10% C: 10% or more and less than 30% D: 30% or more The method for measuring the optical density is the same as in the item (a).

(D-2) A printed matter produced in the same manner as in the above (c) is immersed in tap water at 20 ° C. for 3 seconds, immediately pulled up and dried, and the degree of contamination of the white background portion due to the outflow of the dye. Was evaluated according to the following criteria. A: Almost no pollution B: Little pollution C: Somewhat pollution D: Very much pollution

(D-3) The characters of the printed matter produced in the same manner as in the above (c) are printed in a line direction with a commercially available yellow highlighter pen.
The degree of blurring of characters was evaluated according to the following criteria. A: Almost no fading of characters is recognized B: Little fading of characters C: Many fading of characters

(E) Ejection stability Alphanumeric characters (60 characters x 40 lines) were printed on A4 size plain paper for copying machines (Canon NP paper) and evaluated according to the following criteria. A: No abnormality B: Partial ejection failure or print disorder

(F) Nozzle clogging After the printer was left at room temperature for 2 months, the required number of recovery operations (suction operation by the built-in pump) until the printing became normal was measured and evaluated according to the following criteria. . A: Normal printing is possible with 0 to 1 time B: Normal printing is possible with 2 to 4 times C: Normal printing is possible with 5 to 10 times D: Normal printing is not possible with 11 times

(G) Strikethrough of printed matter A printed matter produced in the same manner as in the item (c) was observed from the back side, and the degree of strikethrough of the ink was evaluated according to the following criteria. A: No strikethrough B: Slight strikethrough C: Fair strikethrough

[0058]

[Table 8]

[0059]

As described above, according to the present invention, it is possible to form a recorded image on various types of plain paper, which has a clear color tone, a high density, and complete water resistance so that bleeding is less likely to occur. Ink having excellent storage stability, good storage stability, no nozzle clogging, and particularly excellent ejection stability during inkjet recording,
An image forming method using the ink and a device using the ink can be provided.

[0060]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a recording head according to an inkjet recording method of the present invention.

FIG. 2 is a schematic cross-sectional view showing a sectional view taken along the line AB of FIG.

FIG. 3 is a schematic external view showing an example of a multi-head in which a large number of heads of FIG. 1 are arranged.

FIG. 4 is a schematic perspective view showing an example of an ink jet recording apparatus incorporating the same head.

FIG. 5 is a schematic cross-sectional view showing an example of an ink cartridge that supplies ink to the head.

FIG. 6 is a schematic external view showing an example of a main part of an inkjet recording apparatus in which the same head and the same ink cartridge are integrated.

[Explanation of symbols]

 13: Head 14: Ink Grooves 15, 28: Heating Head 16: Protective Film 17: Aluminum Electrode 18: Heating Resistor Layer 19: Heat Storage Layer 20: Substrate 21: Ink 22: Discharge Orifice (Fine Hole) 23: Meniscus 24 : Ink droplet 25: Recording material 26: Multi groove 27: Glass plate 40: Ink bag 42: Rubber stopper 44: Ink absorber 45: Ink cartridge 51: Paper feed section 52: Paper feed roller 53: Paper ejection Roller 61: Blade 62: Cap 63: Ink Absorber 64: Ejection Recovery Unit 65: Recording Head 66: Carriage 67: Guide Axis 68: Motor 69: Belt 70: Inkjet Cartridge 71: Head 72: Atmosphere Communication Port

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Tokuya Ota 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (19)

[Claims] 1. An ink comprising a liquid composition containing a colorant and a liquid medium for dissolving or dispersing the colorant, wherein a cationic dye is used as the colorant, represented by the following general formula (A) or (B).
An ink comprising a salt-forming dye salt formed by the salt-forming compound represented by: [In the general formulas (A) and (B), R has 5 to 2 carbon atoms.
2 is an alkyl group, R ¹ is a hydrogen atom or a methyl group,
² is an alkyl group having 5 to 12 carbon atoms, X is -COOM,-
A group selected from SO ₃ M and —OSO ₃ M, M represents a hydrogen atom, an alkali metal or ammonium, n represents 1 or 2, and p represents 0 or 2. ] 2. The ink according to claim 1, wherein the liquid medium is a mixture of water and a water-soluble organic solvent. 3. The ink according to claim 1, further comprising an ethylene oxide adduct of a tertiary alcohol. 4. The ink according to claim 3, wherein the ethylene oxide adduct of the tertiary alcohol is a compound represented by the following general formula (C). [In the formula, L ¹ is-(OCH ₂ CH ₂ ) _x OH, L ² is-(OCH ₂ CH ₂ ) _y OH, and x and y are 1 to 3 respectively.
It represents an integer of 0, and x and y may be the same. ] 5. The ink according to any one of claims 1 to 4, which is used for ink jet recording in which recording is performed by ejecting ink as ink droplets. 6. The ink according to claim 1, wherein the ink droplets are ejected by the action of thermal energy. 7. An image forming method using an ink comprising a liquid composition containing a colorant and a liquid medium for dissolving or dispersing the colorant, wherein a cationic dye is used as the colorant, represented by the following general formula (A): ) Or (B), an image forming method of forming an image by applying an ink containing a salt-forming dye salt-formed with a salt-forming compound to plain paper by an inkjet recording method. [In the general formulas (A) and (B), R has 5 to 2 carbon atoms.
2 is an alkyl group, R ¹ is a hydrogen atom or a methyl group,
² is an alkyl group having 5 to 12 carbon atoms, X is -COOM,-
A group selected from SO ₃ M and —OSO ₃ M, M represents a hydrogen atom, an alkali metal or ammonium, n represents 1 or 2, and p represents 0 or 2. ] 8. The image forming method according to claim 7, wherein the liquid medium is a mixture of water and a water-soluble organic solvent. 9. The image forming method according to claim 8, wherein the ink further contains an ethylene oxide adduct of a tertiary alcohol. 10. The image forming method according to claim 9, wherein the ethylene oxide adduct of the tertiary alcohol is a compound represented by the following general formula (C). [In the formula, L ¹ is-(OCH ₂ CH ₂ ) _x OH, L ² is-(OCH ₂ CH ₂ ) _y OH, and x and y are 1 to 3 respectively.
It represents an integer of 0, and x and y may be the same. ] 11. The image forming method according to claim 7, wherein the ink droplets are ejected by the action of thermal energy. 12. A recording unit comprising an ink containing portion containing ink and a head portion for ejecting the ink as ink droplets, wherein the ink comprises
A recording unit comprising the ink according to claim 4. 13. The head section includes a head for ejecting ink droplets by applying thermal energy to the ink.
The recording unit according to 2. 14. An ink cartridge having an ink containing portion containing ink, wherein the ink is
An ink cartridge which is the ink according to claim 4. 15. An ink jet recording apparatus comprising a recording unit having an ink containing portion containing the ink and a head portion for ejecting the ink as ink droplets, wherein the ink comprises: An inkjet recording apparatus, which is the ink according to Item 4. 16. The head unit includes a head for ejecting ink droplets by applying thermal energy to the ink.
5. The inkjet recording device according to item 5. 17. An ink jet recording apparatus comprising an ink cartridge having an ink containing portion containing ink and a recording head for ejecting the ink as ink droplets, wherein the ink is the ink according to any one of claims 1 to 1. An ink jet recording apparatus which is the ink according to item 4. 18. The ink jet recording apparatus according to claim 17, further comprising an ink supply unit that supplies the ink contained in the ink cartridge to the recording head. 19. The ink jet recording apparatus according to claim 17 or 18, wherein the recording head includes a head that applies thermal energy to the ink to eject ink droplets.